Scientists estimate that in thirty years the oceans will hold a greater mass of plastic than of fish. Almost every biological sample that dredged up from the hadal zone and tested in a lab has been contaminated with microplastics.

“Does it harm the ability of these animals to feed, to maneuver, to reproduce?” McCallum said. “We don’t know, because we can’t compare one that’s full of microplastics with one that’s not. Because there aren’t any.”